Compared to molecular chemistry, nanochemistry is still far from being capable of atomic-level tailoring of particle structure and functionality. Numerous effective methodologies have been developed which can precisely tailor specific groups in organic molecules without altering the major carbon bones, but for nanoparticles, it is still extremely difficult to realize the atomic-level tailoring of specific sites in a particle<br/>without changing the structure of other parts (for example, replacing specific surface motifs, deleting one or two metal atoms, etc.). This issue severely hampers nanochemists to know how different motifs in a nanoparticle contribute to its overall properties. Herein, we demonstrate a site-specific "surgery" on the surface motif of an atomically precise 23-gold-atom [Au23(SR)16]- nanoparticle by a two-step metalexchange<br/>method, which leads to the "resection" of two surface gold atoms and formation of a new 21-gold-atom nanoparticle: [Au21(SR)12(Ph2PCH2PPh2)2]+ without changing the other parts of the starting nanoparticle structure. This precise "surgery" of the nanocluster reveals the different reactivity of the surface motifs and the inner core, the least effect of surface motifs on the optical absorption while a distinct effect on the photoluminescence (i.e. a ten-fold enhancement of luminescence after the tailoring). First principles calculations further reveal the thermodynamically preferred reaction pathway for the formation of [Au21(SR)12(Ph2PCH2PPh2)2]+. This work constitutes a major step toward the development of atomically precise, versatile nanochemistry for precise tailoring of the nanocluster structure for controlling the properties.

Molecular surgery on a 23-gold-atom nanoparticle

254th National Meeting (2017)

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